USGS: No Consistent Nitrate Declines in Mississippi River Basin

The USGS released news of a research effort this morning which finds that there have been no consistent nitrate concentration and loading declines in large Mississippi River Basin rivers over recent years, and that, in fact, the Missouri River, upper Mississippi River and River Basin groundwater are rising sources of nitrate to the Gulf of Mexico.  The release states, in part, that "(d)espite efforts to reduce nitrate levels in the Mississippi River Basin, concentrations and transport at eight major study sites did not consistently decline from 1980-2008. These results are based on a new scientific model developed by the USGS that takes into account variation in river flows in order to gain an accurate understanding of long term trends."

The results of the new USGS study are published in the Journal Environmental Science and Technology (link to the study here).

Major findings of the study are:

• Nitrate transport to the Gulf of Mexico was 10% higher in 2008 than 1980.
• Nitrate concentrations increased considerably at two sites with low concentrations in 1980.
• Nitrate concentrations remained the same or increased at the other six sites, including those where concentrations were relatively high in 1980.
• Increases in nitrate concentrations in groundwater are contributing to increases in river concentrations.